The proposed study focuses on possible hormonal and social factors which determine the psychological significance for the adolescent female of menstruation and menarche. Part I aims to identify the kinds of psychological variability unique to menstruating women and therefore of special significance to the adolescent girl at menarche. It involves a longitudinal study of self-reported moods and activation levels and sensory processes in adult women and men. A second experiment in Part I explores the relationship between diurnal variations in the self-reported moods and activation levels and sensory processes and fluctuations in these processes over the course of the menstrual cycle. The sensory processes are examined in a signal detection paradigm to determine whether sensory sensitivity or decision criteria fluctuate over the course of the cycle. Part II of the proposed research provides data on the validity of questionnaires measuring beliefs about menstruation by determining whether responses on the questionnaires are related to nonverbal behaviors. The hypothesis that beliefs about the psychological concomitants of the menstrual cycle are part of a more general set of beliefs and attitudes toward women is also explored. The aim of this part of the research is to determine the external validity of menstrual distress questionnaires and to examine the range of beliefs and attitudes that may become suddenly and personally salient for the adolescent girl at menarche.